I used to think like you... i was sick last year (i was drunk too!) and it happened so suddenly and was over so quickly that it didn't bother me. however, i think being sick due to alcohol and being sick due to a stomach bug are different things so that is why i generally fear getting stomach bugs more than getting drunk.

i also used to think that if i were sick once, i would adjust to the act and would get used to it but it still feels unnatural to me. i still believe that living your life to the full is the best way to beat this phobia - take a trip abroad, learn to do something new, take up a new hobby.......... the list goes on etc. lol